1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0 2fb32e03fSMathieu Desnoyers# 3fb32e03fSMathieu Desnoyers# General architecture dependent options 4fb32e03fSMathieu Desnoyers# 5125e5645SMathieu Desnoyers 61572497cSChristoph Hellwig# 71572497cSChristoph Hellwig# Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can 81572497cSChristoph Hellwig# override the default values in this file. 91572497cSChristoph Hellwig# 101572497cSChristoph Hellwigsource "arch/$(SRCARCH)/Kconfig" 111572497cSChristoph Hellwig 1222471e13SRandy Dunlapmenu "General architecture-dependent options" 1322471e13SRandy Dunlap 14692f66f2SHari Bathiniconfig CRASH_CORE 15692f66f2SHari Bathini bool 16692f66f2SHari Bathini 172965faa5SDave Youngconfig KEXEC_CORE 18692f66f2SHari Bathini select CRASH_CORE 192965faa5SDave Young bool 202965faa5SDave Young 21467d2782SThiago Jung Bauermannconfig HAVE_IMA_KEXEC 22467d2782SThiago Jung Bauermann bool 23467d2782SThiago Jung Bauermann 2405736e4aSThomas Gleixnerconfig HOTPLUG_SMT 2505736e4aSThomas Gleixner bool 2605736e4aSThomas Gleixner 27125e5645SMathieu Desnoyersconfig OPROFILE 28b309a294SRobert Richter tristate "OProfile system profiling" 29125e5645SMathieu Desnoyers depends on PROFILING 30125e5645SMathieu Desnoyers depends on HAVE_OPROFILE 31d69d59f4SIngo Molnar select RING_BUFFER 329a5963ebSChristian Borntraeger select RING_BUFFER_ALLOW_SWAP 33125e5645SMathieu Desnoyers help 34125e5645SMathieu Desnoyers OProfile is a profiling system capable of profiling the 35125e5645SMathieu Desnoyers whole system, include the kernel, kernel modules, libraries, 36125e5645SMathieu Desnoyers and applications. 37125e5645SMathieu Desnoyers 38125e5645SMathieu Desnoyers If unsure, say N. 39125e5645SMathieu Desnoyers 404d4036e0SJason Yehconfig OPROFILE_EVENT_MULTIPLEX 414d4036e0SJason Yeh bool "OProfile multiplexing support (EXPERIMENTAL)" 424d4036e0SJason Yeh default n 434d4036e0SJason Yeh depends on OPROFILE && X86 444d4036e0SJason Yeh help 454d4036e0SJason Yeh The number of hardware counters is limited. The multiplexing 464d4036e0SJason Yeh feature enables OProfile to gather more events than counters 474d4036e0SJason Yeh are provided by the hardware. This is realized by switching 489332ef9dSMasahiro Yamada between events at a user specified time interval. 494d4036e0SJason Yeh 504d4036e0SJason Yeh If unsure, say N. 514d4036e0SJason Yeh 52125e5645SMathieu Desnoyersconfig HAVE_OPROFILE 539ba16087SJan Beulich bool 54125e5645SMathieu Desnoyers 55dcfce4a0SRobert Richterconfig OPROFILE_NMI_TIMER 56dcfce4a0SRobert Richter def_bool y 57af9feebeSAnton Blanchard depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64 58dcfce4a0SRobert Richter 59125e5645SMathieu Desnoyersconfig KPROBES 60125e5645SMathieu Desnoyers bool "Kprobes" 6105ed160eSMasami Hiramatsu depends on MODULES 62125e5645SMathieu Desnoyers depends on HAVE_KPROBES 6305ed160eSMasami Hiramatsu select KALLSYMS 64125e5645SMathieu Desnoyers help 65125e5645SMathieu Desnoyers Kprobes allows you to trap at almost any kernel address and 66125e5645SMathieu Desnoyers execute a callback function. register_kprobe() establishes 67125e5645SMathieu Desnoyers a probepoint and specifies the callback. Kprobes is useful 68125e5645SMathieu Desnoyers for kernel debugging, non-intrusive instrumentation and testing. 69125e5645SMathieu Desnoyers If in doubt, say "N". 70125e5645SMathieu Desnoyers 7145f81b1cSSteven Rostedtconfig JUMP_LABEL 72c5905afbSIngo Molnar bool "Optimize very unlikely/likely branches" 7345f81b1cSSteven Rostedt depends on HAVE_ARCH_JUMP_LABEL 74e9666d10SMasahiro Yamada depends on CC_HAS_ASM_GOTO 7545f81b1cSSteven Rostedt help 76c5905afbSIngo Molnar This option enables a transparent branch optimization that 77c5905afbSIngo Molnar makes certain almost-always-true or almost-always-false branch 78c5905afbSIngo Molnar conditions even cheaper to execute within the kernel. 7945f81b1cSSteven Rostedt 80c5905afbSIngo Molnar Certain performance-sensitive kernel code, such as trace points, 81c5905afbSIngo Molnar scheduler functionality, networking code and KVM have such 82c5905afbSIngo Molnar branches and include support for this optimization technique. 83c5905afbSIngo Molnar 84c5905afbSIngo Molnar If it is detected that the compiler has support for "asm goto", 85c5905afbSIngo Molnar the kernel will compile such branches with just a nop 86c5905afbSIngo Molnar instruction. When the condition flag is toggled to true, the 87c5905afbSIngo Molnar nop will be converted to a jump instruction to execute the 88c5905afbSIngo Molnar conditional block of instructions. 89c5905afbSIngo Molnar 90c5905afbSIngo Molnar This technique lowers overhead and stress on the branch prediction 91c5905afbSIngo Molnar of the processor and generally makes the kernel faster. The update 92c5905afbSIngo Molnar of the condition is slower, but those are always very rare. 93c5905afbSIngo Molnar 94c5905afbSIngo Molnar ( On 32-bit x86, the necessary options added to the compiler 95c5905afbSIngo Molnar flags may increase the size of the kernel slightly. ) 9645f81b1cSSteven Rostedt 971987c947SPeter Zijlstraconfig STATIC_KEYS_SELFTEST 981987c947SPeter Zijlstra bool "Static key selftest" 991987c947SPeter Zijlstra depends on JUMP_LABEL 1001987c947SPeter Zijlstra help 1011987c947SPeter Zijlstra Boot time self-test of the branch patching code. 1021987c947SPeter Zijlstra 103afd66255SMasami Hiramatsuconfig OPTPROBES 1045cc718b9SMasami Hiramatsu def_bool y 1055cc718b9SMasami Hiramatsu depends on KPROBES && HAVE_OPTPROBES 10601b1d88bSThomas Gleixner select TASKS_RCU if PREEMPTION 107afd66255SMasami Hiramatsu 108e7dbfe34SMasami Hiramatsuconfig KPROBES_ON_FTRACE 109e7dbfe34SMasami Hiramatsu def_bool y 110e7dbfe34SMasami Hiramatsu depends on KPROBES && HAVE_KPROBES_ON_FTRACE 111e7dbfe34SMasami Hiramatsu depends on DYNAMIC_FTRACE_WITH_REGS 112e7dbfe34SMasami Hiramatsu help 113e7dbfe34SMasami Hiramatsu If function tracer is enabled and the arch supports full 114e7dbfe34SMasami Hiramatsu passing of pt_regs to function tracing, then kprobes can 115e7dbfe34SMasami Hiramatsu optimize on top of function tracing. 116e7dbfe34SMasami Hiramatsu 1172b144498SSrikar Dronamrajuconfig UPROBES 11809294e31SDavid A. Long def_bool n 119e8f4aa60SAllen Pais depends on ARCH_SUPPORTS_UPROBES 1202b144498SSrikar Dronamraju help 1217b2d81d4SIngo Molnar Uprobes is the user-space counterpart to kprobes: they 1227b2d81d4SIngo Molnar enable instrumentation applications (such as 'perf probe') 1237b2d81d4SIngo Molnar to establish unintrusive probes in user-space binaries and 1247b2d81d4SIngo Molnar libraries, by executing handler functions when the probes 1257b2d81d4SIngo Molnar are hit by user-space applications. 1267b2d81d4SIngo Molnar 1277b2d81d4SIngo Molnar ( These probes come in the form of single-byte breakpoints, 1287b2d81d4SIngo Molnar managed by the kernel and kept transparent to the probed 1297b2d81d4SIngo Molnar application. ) 1302b144498SSrikar Dronamraju 13158340a07SJohannes Bergconfig HAVE_EFFICIENT_UNALIGNED_ACCESS 1329ba16087SJan Beulich bool 13358340a07SJohannes Berg help 13458340a07SJohannes Berg Some architectures are unable to perform unaligned accesses 13558340a07SJohannes Berg without the use of get_unaligned/put_unaligned. Others are 13658340a07SJohannes Berg unable to perform such accesses efficiently (e.g. trap on 13758340a07SJohannes Berg unaligned access and require fixing it up in the exception 13858340a07SJohannes Berg handler.) 13958340a07SJohannes Berg 14058340a07SJohannes Berg This symbol should be selected by an architecture if it can 14158340a07SJohannes Berg perform unaligned accesses efficiently to allow different 14258340a07SJohannes Berg code paths to be selected for these cases. Some network 14358340a07SJohannes Berg drivers, for example, could opt to not fix up alignment 14458340a07SJohannes Berg problems with received packets if doing so would not help 14558340a07SJohannes Berg much. 14658340a07SJohannes Berg 14758340a07SJohannes Berg See Documentation/unaligned-memory-access.txt for more 14858340a07SJohannes Berg information on the topic of unaligned memory accesses. 14958340a07SJohannes Berg 150cf66bb93SDavid Woodhouseconfig ARCH_USE_BUILTIN_BSWAP 151cf66bb93SDavid Woodhouse bool 152cf66bb93SDavid Woodhouse help 153cf66bb93SDavid Woodhouse Modern versions of GCC (since 4.4) have builtin functions 154cf66bb93SDavid Woodhouse for handling byte-swapping. Using these, instead of the old 155cf66bb93SDavid Woodhouse inline assembler that the architecture code provides in the 156cf66bb93SDavid Woodhouse __arch_bswapXX() macros, allows the compiler to see what's 157cf66bb93SDavid Woodhouse happening and offers more opportunity for optimisation. In 158cf66bb93SDavid Woodhouse particular, the compiler will be able to combine the byteswap 159cf66bb93SDavid Woodhouse with a nearby load or store and use load-and-swap or 160cf66bb93SDavid Woodhouse store-and-swap instructions if the architecture has them. It 161cf66bb93SDavid Woodhouse should almost *never* result in code which is worse than the 162cf66bb93SDavid Woodhouse hand-coded assembler in <asm/swab.h>. But just in case it 163cf66bb93SDavid Woodhouse does, the use of the builtins is optional. 164cf66bb93SDavid Woodhouse 165cf66bb93SDavid Woodhouse Any architecture with load-and-swap or store-and-swap 166cf66bb93SDavid Woodhouse instructions should set this. And it shouldn't hurt to set it 167cf66bb93SDavid Woodhouse on architectures that don't have such instructions. 168cf66bb93SDavid Woodhouse 1699edddaa2SAnanth N Mavinakayanahalliconfig KRETPROBES 1709edddaa2SAnanth N Mavinakayanahalli def_bool y 1719edddaa2SAnanth N Mavinakayanahalli depends on KPROBES && HAVE_KRETPROBES 1729edddaa2SAnanth N Mavinakayanahalli 1737c68af6eSAvi Kivityconfig USER_RETURN_NOTIFIER 1747c68af6eSAvi Kivity bool 1757c68af6eSAvi Kivity depends on HAVE_USER_RETURN_NOTIFIER 1767c68af6eSAvi Kivity help 1777c68af6eSAvi Kivity Provide a kernel-internal notification when a cpu is about to 1787c68af6eSAvi Kivity switch to user mode. 1797c68af6eSAvi Kivity 18028b2ee20SRik van Rielconfig HAVE_IOREMAP_PROT 1819ba16087SJan Beulich bool 18228b2ee20SRik van Riel 183125e5645SMathieu Desnoyersconfig HAVE_KPROBES 1849ba16087SJan Beulich bool 1859edddaa2SAnanth N Mavinakayanahalli 1869edddaa2SAnanth N Mavinakayanahalliconfig HAVE_KRETPROBES 1879ba16087SJan Beulich bool 18874bc7ceeSArthur Kepner 189afd66255SMasami Hiramatsuconfig HAVE_OPTPROBES 190afd66255SMasami Hiramatsu bool 191d314d74cSCong Wang 192e7dbfe34SMasami Hiramatsuconfig HAVE_KPROBES_ON_FTRACE 193e7dbfe34SMasami Hiramatsu bool 194e7dbfe34SMasami Hiramatsu 195540adea3SMasami Hiramatsuconfig HAVE_FUNCTION_ERROR_INJECTION 1969802d865SJosef Bacik bool 1979802d865SJosef Bacik 19842a0bb3fSPetr Mladekconfig HAVE_NMI 19942a0bb3fSPetr Mladek bool 20042a0bb3fSPetr Mladek 2011f5a4ad9SRoland McGrath# 2021f5a4ad9SRoland McGrath# An arch should select this if it provides all these things: 2031f5a4ad9SRoland McGrath# 2041f5a4ad9SRoland McGrath# task_pt_regs() in asm/processor.h or asm/ptrace.h 2051f5a4ad9SRoland McGrath# arch_has_single_step() if there is hardware single-step support 2061f5a4ad9SRoland McGrath# arch_has_block_step() if there is hardware block-step support 2071f5a4ad9SRoland McGrath# asm/syscall.h supplying asm-generic/syscall.h interface 2081f5a4ad9SRoland McGrath# linux/regset.h user_regset interfaces 2091f5a4ad9SRoland McGrath# CORE_DUMP_USE_REGSET #define'd in linux/elf.h 2101f5a4ad9SRoland McGrath# TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 2111f5a4ad9SRoland McGrath# TIF_NOTIFY_RESUME calls tracehook_notify_resume() 2121f5a4ad9SRoland McGrath# signal delivery calls tracehook_signal_handler() 2131f5a4ad9SRoland McGrath# 2141f5a4ad9SRoland McGrathconfig HAVE_ARCH_TRACEHOOK 2159ba16087SJan Beulich bool 2161f5a4ad9SRoland McGrath 217c64be2bbSMarek Szyprowskiconfig HAVE_DMA_CONTIGUOUS 218c64be2bbSMarek Szyprowski bool 219c64be2bbSMarek Szyprowski 22029d5e047SThomas Gleixnerconfig GENERIC_SMP_IDLE_THREAD 22129d5e047SThomas Gleixner bool 22229d5e047SThomas Gleixner 223485cf5daSKevin Hilmanconfig GENERIC_IDLE_POLL_SETUP 224485cf5daSKevin Hilman bool 225485cf5daSKevin Hilman 2266974f0c4SDaniel Micayconfig ARCH_HAS_FORTIFY_SOURCE 2276974f0c4SDaniel Micay bool 2286974f0c4SDaniel Micay help 2296974f0c4SDaniel Micay An architecture should select this when it can successfully 2306974f0c4SDaniel Micay build and run with CONFIG_FORTIFY_SOURCE. 2316974f0c4SDaniel Micay 232d8ae8a37SChristoph Hellwig# 233d8ae8a37SChristoph Hellwig# Select if the arch provides a historic keepinit alias for the retain_initrd 234d8ae8a37SChristoph Hellwig# command line option 235d8ae8a37SChristoph Hellwig# 236d8ae8a37SChristoph Hellwigconfig ARCH_HAS_KEEPINITRD 237d8ae8a37SChristoph Hellwig bool 238d8ae8a37SChristoph Hellwig 239d2852a22SDaniel Borkmann# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h 240d2852a22SDaniel Borkmannconfig ARCH_HAS_SET_MEMORY 241d2852a22SDaniel Borkmann bool 242d2852a22SDaniel Borkmann 243d253ca0cSRick Edgecombe# Select if arch has all set_direct_map_invalid/default() functions 244d253ca0cSRick Edgecombeconfig ARCH_HAS_SET_DIRECT_MAP 245d253ca0cSRick Edgecombe bool 246d253ca0cSRick Edgecombe 247c30700dbSChristoph Hellwig# 248c30700dbSChristoph Hellwig# Select if arch has an uncached kernel segment and provides the 249c30700dbSChristoph Hellwig# uncached_kernel_address / cached_kernel_address symbols to use it 250c30700dbSChristoph Hellwig# 251c30700dbSChristoph Hellwigconfig ARCH_HAS_UNCACHED_SEGMENT 252c30700dbSChristoph Hellwig select ARCH_HAS_DMA_PREP_COHERENT 253c30700dbSChristoph Hellwig bool 254c30700dbSChristoph Hellwig 2550500871fSDavid Howells# Select if arch init_task must go in the __init_task_data section 2560500871fSDavid Howellsconfig ARCH_TASK_STRUCT_ON_STACK 257a4a2eb49SThomas Gleixner bool 258a4a2eb49SThomas Gleixner 259f5e10287SThomas Gleixner# Select if arch has its private alloc_task_struct() function 260f5e10287SThomas Gleixnerconfig ARCH_TASK_STRUCT_ALLOCATOR 261f5e10287SThomas Gleixner bool 262f5e10287SThomas Gleixner 2635905429aSKees Cookconfig HAVE_ARCH_THREAD_STRUCT_WHITELIST 2645905429aSKees Cook bool 2655905429aSKees Cook depends on !ARCH_TASK_STRUCT_ALLOCATOR 2665905429aSKees Cook help 2675905429aSKees Cook An architecture should select this to provide hardened usercopy 2685905429aSKees Cook knowledge about what region of the thread_struct should be 2695905429aSKees Cook whitelisted for copying to userspace. Normally this is only the 2705905429aSKees Cook FPU registers. Specifically, arch_thread_struct_whitelist() 2715905429aSKees Cook should be implemented. Without this, the entire thread_struct 2725905429aSKees Cook field in task_struct will be left whitelisted. 2735905429aSKees Cook 274b235beeaSLinus Torvalds# Select if arch has its private alloc_thread_stack() function 275b235beeaSLinus Torvaldsconfig ARCH_THREAD_STACK_ALLOCATOR 276f5e10287SThomas Gleixner bool 277f5e10287SThomas Gleixner 2785aaeb5c0SIngo Molnar# Select if arch wants to size task_struct dynamically via arch_task_struct_size: 2795aaeb5c0SIngo Molnarconfig ARCH_WANTS_DYNAMIC_TASK_STRUCT 2805aaeb5c0SIngo Molnar bool 2815aaeb5c0SIngo Molnar 282942fa985SYury Norovconfig ARCH_32BIT_OFF_T 283942fa985SYury Norov bool 284942fa985SYury Norov depends on !64BIT 285942fa985SYury Norov help 286942fa985SYury Norov All new 32-bit architectures should have 64-bit off_t type on 287942fa985SYury Norov userspace side which corresponds to the loff_t kernel type. This 288942fa985SYury Norov is the requirement for modern ABIs. Some existing architectures 289942fa985SYury Norov still support 32-bit off_t. This option is enabled for all such 290942fa985SYury Norov architectures explicitly. 291942fa985SYury Norov 292f850c30cSHeiko Carstensconfig HAVE_REGS_AND_STACK_ACCESS_API 293f850c30cSHeiko Carstens bool 294e01292b1SHeiko Carstens help 295e01292b1SHeiko Carstens This symbol should be selected by an architecure if it supports 296e01292b1SHeiko Carstens the API needed to access registers and stack entries from pt_regs, 297e01292b1SHeiko Carstens declared in asm/ptrace.h 298e01292b1SHeiko Carstens For example the kprobes-based event tracer needs this API. 299f850c30cSHeiko Carstens 300d7822b1eSMathieu Desnoyersconfig HAVE_RSEQ 301d7822b1eSMathieu Desnoyers bool 302d7822b1eSMathieu Desnoyers depends on HAVE_REGS_AND_STACK_ACCESS_API 303d7822b1eSMathieu Desnoyers help 304d7822b1eSMathieu Desnoyers This symbol should be selected by an architecture if it 305d7822b1eSMathieu Desnoyers supports an implementation of restartable sequences. 306d7822b1eSMathieu Desnoyers 3073c88ee19SMasami Hiramatsuconfig HAVE_FUNCTION_ARG_ACCESS_API 3083c88ee19SMasami Hiramatsu bool 3093c88ee19SMasami Hiramatsu help 3103c88ee19SMasami Hiramatsu This symbol should be selected by an architecure if it supports 3113c88ee19SMasami Hiramatsu the API needed to access function arguments from pt_regs, 3123c88ee19SMasami Hiramatsu declared in asm/ptrace.h 3133c88ee19SMasami Hiramatsu 3149483a578SDavid Brownellconfig HAVE_CLK 3159ba16087SJan Beulich bool 3169483a578SDavid Brownell help 3179483a578SDavid Brownell The <linux/clk.h> calls support software clock gating and 3189483a578SDavid Brownell thus are a key power management tool on many systems. 3199483a578SDavid Brownell 32062a038d3SK.Prasadconfig HAVE_HW_BREAKPOINT 32162a038d3SK.Prasad bool 32299e8c5a3SFrederic Weisbecker depends on PERF_EVENTS 32362a038d3SK.Prasad 3240102752eSFrederic Weisbeckerconfig HAVE_MIXED_BREAKPOINTS_REGS 3250102752eSFrederic Weisbecker bool 3260102752eSFrederic Weisbecker depends on HAVE_HW_BREAKPOINT 3270102752eSFrederic Weisbecker help 3280102752eSFrederic Weisbecker Depending on the arch implementation of hardware breakpoints, 3290102752eSFrederic Weisbecker some of them have separate registers for data and instruction 3300102752eSFrederic Weisbecker breakpoints addresses, others have mixed registers to store 3310102752eSFrederic Weisbecker them but define the access type in a control register. 3320102752eSFrederic Weisbecker Select this option if your arch implements breakpoints under the 3330102752eSFrederic Weisbecker latter fashion. 3340102752eSFrederic Weisbecker 3357c68af6eSAvi Kivityconfig HAVE_USER_RETURN_NOTIFIER 3367c68af6eSAvi Kivity bool 337a1922ed6SIngo Molnar 338c01d4323SFrederic Weisbeckerconfig HAVE_PERF_EVENTS_NMI 339c01d4323SFrederic Weisbecker bool 34023637d47SFrederic Weisbecker help 34123637d47SFrederic Weisbecker System hardware can generate an NMI using the perf event 34223637d47SFrederic Weisbecker subsystem. Also has support for calculating CPU cycle events 34323637d47SFrederic Weisbecker to determine how many clock cycles in a given period. 344c01d4323SFrederic Weisbecker 34505a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_PERF 34605a4a952SNicholas Piggin bool 34705a4a952SNicholas Piggin depends on HAVE_PERF_EVENTS_NMI 34805a4a952SNicholas Piggin help 34905a4a952SNicholas Piggin The arch chooses to use the generic perf-NMI-based hardlockup 35005a4a952SNicholas Piggin detector. Must define HAVE_PERF_EVENTS_NMI. 35105a4a952SNicholas Piggin 35205a4a952SNicholas Pigginconfig HAVE_NMI_WATCHDOG 35305a4a952SNicholas Piggin depends on HAVE_NMI 35405a4a952SNicholas Piggin bool 35505a4a952SNicholas Piggin help 35605a4a952SNicholas Piggin The arch provides a low level NMI watchdog. It provides 35705a4a952SNicholas Piggin asm/nmi.h, and defines its own arch_touch_nmi_watchdog(). 35805a4a952SNicholas Piggin 35905a4a952SNicholas Pigginconfig HAVE_HARDLOCKUP_DETECTOR_ARCH 36005a4a952SNicholas Piggin bool 36105a4a952SNicholas Piggin select HAVE_NMI_WATCHDOG 36205a4a952SNicholas Piggin help 36305a4a952SNicholas Piggin The arch chooses to provide its own hardlockup detector, which is 36405a4a952SNicholas Piggin a superset of the HAVE_NMI_WATCHDOG. It also conforms to config 36505a4a952SNicholas Piggin interfaces and parameters provided by hardlockup detector subsystem. 36605a4a952SNicholas Piggin 367c5e63197SJiri Olsaconfig HAVE_PERF_REGS 368c5e63197SJiri Olsa bool 369c5e63197SJiri Olsa help 370c5e63197SJiri Olsa Support selective register dumps for perf events. This includes 371c5e63197SJiri Olsa bit-mapping of each registers and a unique architecture id. 372c5e63197SJiri Olsa 373c5ebcedbSJiri Olsaconfig HAVE_PERF_USER_STACK_DUMP 374c5ebcedbSJiri Olsa bool 375c5ebcedbSJiri Olsa help 376c5ebcedbSJiri Olsa Support user stack dumps for perf event samples. This needs 377c5ebcedbSJiri Olsa access to the user stack pointer which is not unified across 378c5ebcedbSJiri Olsa architectures. 379c5ebcedbSJiri Olsa 380bf5438fcSJason Baronconfig HAVE_ARCH_JUMP_LABEL 381bf5438fcSJason Baron bool 382bf5438fcSJason Baron 38350ff18abSArd Biesheuvelconfig HAVE_ARCH_JUMP_LABEL_RELATIVE 38450ff18abSArd Biesheuvel bool 38550ff18abSArd Biesheuvel 38626723911SPeter Zijlstraconfig HAVE_RCU_TABLE_FREE 38726723911SPeter Zijlstra bool 38826723911SPeter Zijlstra 38996bc9567SPeter Zijlstraconfig HAVE_RCU_TABLE_NO_INVALIDATE 390d86564a2SPeter Zijlstra bool 391d86564a2SPeter Zijlstra 392ed6a7935SPeter Zijlstraconfig HAVE_MMU_GATHER_PAGE_SIZE 393ed6a7935SPeter Zijlstra bool 394ed6a7935SPeter Zijlstra 395952a31c9SMartin Schwidefskyconfig HAVE_MMU_GATHER_NO_GATHER 396952a31c9SMartin Schwidefsky bool 397952a31c9SMartin Schwidefsky 398df013ffbSHuang Yingconfig ARCH_HAVE_NMI_SAFE_CMPXCHG 399df013ffbSHuang Ying bool 400df013ffbSHuang Ying 40143570fd2SHeiko Carstensconfig HAVE_ALIGNED_STRUCT_PAGE 40243570fd2SHeiko Carstens bool 40343570fd2SHeiko Carstens help 40443570fd2SHeiko Carstens This makes sure that struct pages are double word aligned and that 40543570fd2SHeiko Carstens e.g. the SLUB allocator can perform double word atomic operations 40643570fd2SHeiko Carstens on a struct page for better performance. However selecting this 40743570fd2SHeiko Carstens might increase the size of a struct page by a word. 40843570fd2SHeiko Carstens 4094156153cSHeiko Carstensconfig HAVE_CMPXCHG_LOCAL 4104156153cSHeiko Carstens bool 4114156153cSHeiko Carstens 4122565409fSHeiko Carstensconfig HAVE_CMPXCHG_DOUBLE 4132565409fSHeiko Carstens bool 4142565409fSHeiko Carstens 41577e58496SPaul E. McKenneyconfig ARCH_WEAK_RELEASE_ACQUIRE 41677e58496SPaul E. McKenney bool 41777e58496SPaul E. McKenney 418c1d7e01dSWill Deaconconfig ARCH_WANT_IPC_PARSE_VERSION 419c1d7e01dSWill Deacon bool 420c1d7e01dSWill Deacon 421c1d7e01dSWill Deaconconfig ARCH_WANT_COMPAT_IPC_PARSE_VERSION 422c1d7e01dSWill Deacon bool 423c1d7e01dSWill Deacon 42448b25c43SChris Metcalfconfig ARCH_WANT_OLD_COMPAT_IPC 425c1d7e01dSWill Deacon select ARCH_WANT_COMPAT_IPC_PARSE_VERSION 42648b25c43SChris Metcalf bool 42748b25c43SChris Metcalf 428e2cfabdfSWill Drewryconfig HAVE_ARCH_SECCOMP_FILTER 429e2cfabdfSWill Drewry bool 430e2cfabdfSWill Drewry help 431fb0fadf9SWill Drewry An arch should select this symbol if it provides all of these things: 432bb6ea430SWill Drewry - syscall_get_arch() 433bb6ea430SWill Drewry - syscall_get_arguments() 434bb6ea430SWill Drewry - syscall_rollback() 435bb6ea430SWill Drewry - syscall_set_return_value() 436fb0fadf9SWill Drewry - SIGSYS siginfo_t support 437fb0fadf9SWill Drewry - secure_computing is called from a ptrace_event()-safe context 438fb0fadf9SWill Drewry - secure_computing return value is checked and a return value of -1 439fb0fadf9SWill Drewry results in the system call being skipped immediately. 44048dc92b9SKees Cook - seccomp syscall wired up 441e2cfabdfSWill Drewry 442e2cfabdfSWill Drewryconfig SECCOMP_FILTER 443e2cfabdfSWill Drewry def_bool y 444e2cfabdfSWill Drewry depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET 445e2cfabdfSWill Drewry help 446e2cfabdfSWill Drewry Enable tasks to build secure computing environments defined 447e2cfabdfSWill Drewry in terms of Berkeley Packet Filter programs which implement 448e2cfabdfSWill Drewry task-defined system call filtering polices. 449e2cfabdfSWill Drewry 4505fb94e9cSMauro Carvalho Chehab See Documentation/userspace-api/seccomp_filter.rst for details. 451e2cfabdfSWill Drewry 452afaef01cSAlexander Popovconfig HAVE_ARCH_STACKLEAK 453afaef01cSAlexander Popov bool 454afaef01cSAlexander Popov help 455afaef01cSAlexander Popov An architecture should select this if it has the code which 456afaef01cSAlexander Popov fills the used part of the kernel stack with the STACKLEAK_POISON 457afaef01cSAlexander Popov value before returning from system calls. 458afaef01cSAlexander Popov 459d148eac0SMasahiro Yamadaconfig HAVE_STACKPROTECTOR 46019952a92SKees Cook bool 46119952a92SKees Cook help 46219952a92SKees Cook An arch should select this symbol if: 46319952a92SKees Cook - it has implemented a stack canary (e.g. __stack_chk_guard) 46419952a92SKees Cook 4652a61f474SMasahiro Yamadaconfig CC_HAS_STACKPROTECTOR_NONE 4662a61f474SMasahiro Yamada def_bool $(cc-option,-fno-stack-protector) 4672a61f474SMasahiro Yamada 468050e9baaSLinus Torvaldsconfig STACKPROTECTOR 4692a61f474SMasahiro Yamada bool "Stack Protector buffer overflow detection" 470d148eac0SMasahiro Yamada depends on HAVE_STACKPROTECTOR 4712a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector) 4722a61f474SMasahiro Yamada default y 4738779657dSKees Cook help 4748779657dSKees Cook This option turns on the "stack-protector" GCC feature. This 47519952a92SKees Cook feature puts, at the beginning of functions, a canary value on 47619952a92SKees Cook the stack just before the return address, and validates 47719952a92SKees Cook the value just before actually returning. Stack based buffer 47819952a92SKees Cook overflows (that need to overwrite this return address) now also 47919952a92SKees Cook overwrite the canary, which gets detected and the attack is then 48019952a92SKees Cook neutralized via a kernel panic. 48119952a92SKees Cook 4828779657dSKees Cook Functions will have the stack-protector canary logic added if they 4838779657dSKees Cook have an 8-byte or larger character array on the stack. 4848779657dSKees Cook 48519952a92SKees Cook This feature requires gcc version 4.2 or above, or a distribution 4868779657dSKees Cook gcc with the feature backported ("-fstack-protector"). 4878779657dSKees Cook 4888779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 4898779657dSKees Cook about 3% of all kernel functions, which increases kernel code size 4908779657dSKees Cook by about 0.3%. 4918779657dSKees Cook 492050e9baaSLinus Torvaldsconfig STACKPROTECTOR_STRONG 4932a61f474SMasahiro Yamada bool "Strong Stack Protector" 494050e9baaSLinus Torvalds depends on STACKPROTECTOR 4952a61f474SMasahiro Yamada depends on $(cc-option,-fstack-protector-strong) 4962a61f474SMasahiro Yamada default y 4978779657dSKees Cook help 4988779657dSKees Cook Functions will have the stack-protector canary logic added in any 4998779657dSKees Cook of the following conditions: 5008779657dSKees Cook 5018779657dSKees Cook - local variable's address used as part of the right hand side of an 5028779657dSKees Cook assignment or function argument 5038779657dSKees Cook - local variable is an array (or union containing an array), 5048779657dSKees Cook regardless of array type or length 5058779657dSKees Cook - uses register local variables 5068779657dSKees Cook 5078779657dSKees Cook This feature requires gcc version 4.9 or above, or a distribution 5088779657dSKees Cook gcc with the feature backported ("-fstack-protector-strong"). 5098779657dSKees Cook 5108779657dSKees Cook On an x86 "defconfig" build, this feature adds canary checks to 5118779657dSKees Cook about 20% of all kernel functions, which increases the kernel code 5128779657dSKees Cook size by about 2%. 5138779657dSKees Cook 5140f60a8efSKees Cookconfig HAVE_ARCH_WITHIN_STACK_FRAMES 5150f60a8efSKees Cook bool 5160f60a8efSKees Cook help 5170f60a8efSKees Cook An architecture should select this if it can walk the kernel stack 5180f60a8efSKees Cook frames to determine if an object is part of either the arguments 5190f60a8efSKees Cook or local variables (i.e. that it excludes saved return addresses, 5200f60a8efSKees Cook and similar) by implementing an inline arch_within_stack_frames(), 5210f60a8efSKees Cook which is used by CONFIG_HARDENED_USERCOPY. 5220f60a8efSKees Cook 52391d1aa43SFrederic Weisbeckerconfig HAVE_CONTEXT_TRACKING 5242b1d5024SFrederic Weisbecker bool 5252b1d5024SFrederic Weisbecker help 52691d1aa43SFrederic Weisbecker Provide kernel/user boundaries probes necessary for subsystems 52791d1aa43SFrederic Weisbecker that need it, such as userspace RCU extended quiescent state. 52891d1aa43SFrederic Weisbecker Syscalls need to be wrapped inside user_exit()-user_enter() through 52991d1aa43SFrederic Weisbecker the slow path using TIF_NOHZ flag. Exceptions handlers must be 53091d1aa43SFrederic Weisbecker wrapped as well. Irqs are already protected inside 53191d1aa43SFrederic Weisbecker rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on 53291d1aa43SFrederic Weisbecker irq exit still need to be protected. 5332b1d5024SFrederic Weisbecker 534b952741cSFrederic Weisbeckerconfig HAVE_VIRT_CPU_ACCOUNTING 535b952741cSFrederic Weisbecker bool 536b952741cSFrederic Weisbecker 53740565b5aSStanislaw Gruszkaconfig ARCH_HAS_SCALED_CPUTIME 53840565b5aSStanislaw Gruszka bool 53940565b5aSStanislaw Gruszka 540554b0004SKevin Hilmanconfig HAVE_VIRT_CPU_ACCOUNTING_GEN 541554b0004SKevin Hilman bool 542554b0004SKevin Hilman default y if 64BIT 543554b0004SKevin Hilman help 544554b0004SKevin Hilman With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. 545554b0004SKevin Hilman Before enabling this option, arch code must be audited 546554b0004SKevin Hilman to ensure there are no races in concurrent read/write of 547554b0004SKevin Hilman cputime_t. For example, reading/writing 64-bit cputime_t on 548554b0004SKevin Hilman some 32-bit arches may require multiple accesses, so proper 549554b0004SKevin Hilman locking is needed to protect against concurrent accesses. 550554b0004SKevin Hilman 551554b0004SKevin Hilman 552fdf9c356SFrederic Weisbeckerconfig HAVE_IRQ_TIME_ACCOUNTING 553fdf9c356SFrederic Weisbecker bool 554fdf9c356SFrederic Weisbecker help 555fdf9c356SFrederic Weisbecker Archs need to ensure they use a high enough resolution clock to 556fdf9c356SFrederic Weisbecker support irq time accounting and then call enable_sched_clock_irqtime(). 557fdf9c356SFrederic Weisbecker 5582c91bd4aSJoel Fernandes (Google)config HAVE_MOVE_PMD 5592c91bd4aSJoel Fernandes (Google) bool 5602c91bd4aSJoel Fernandes (Google) help 5612c91bd4aSJoel Fernandes (Google) Archs that select this are able to move page tables at the PMD level. 5622c91bd4aSJoel Fernandes (Google) 56315626062SGerald Schaeferconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE 56415626062SGerald Schaefer bool 56515626062SGerald Schaefer 566a00cc7d9SMatthew Wilcoxconfig HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 567a00cc7d9SMatthew Wilcox bool 568a00cc7d9SMatthew Wilcox 5690ddab1d2SToshi Kaniconfig HAVE_ARCH_HUGE_VMAP 5700ddab1d2SToshi Kani bool 5710ddab1d2SToshi Kani 5723876d4a3SAlexandre Ghiticonfig ARCH_WANT_HUGE_PMD_SHARE 5733876d4a3SAlexandre Ghiti bool 5743876d4a3SAlexandre Ghiti 5750f8975ecSPavel Emelyanovconfig HAVE_ARCH_SOFT_DIRTY 5760f8975ecSPavel Emelyanov bool 5770f8975ecSPavel Emelyanov 578786d35d4SDavid Howellsconfig HAVE_MOD_ARCH_SPECIFIC 579786d35d4SDavid Howells bool 580786d35d4SDavid Howells help 581786d35d4SDavid Howells The arch uses struct mod_arch_specific to store data. Many arches 582786d35d4SDavid Howells just need a simple module loader without arch specific data - those 583786d35d4SDavid Howells should not enable this. 584786d35d4SDavid Howells 585786d35d4SDavid Howellsconfig MODULES_USE_ELF_RELA 586786d35d4SDavid Howells bool 587786d35d4SDavid Howells help 588786d35d4SDavid Howells Modules only use ELF RELA relocations. Modules with ELF REL 589786d35d4SDavid Howells relocations will give an error. 590786d35d4SDavid Howells 591786d35d4SDavid Howellsconfig MODULES_USE_ELF_REL 592786d35d4SDavid Howells bool 593786d35d4SDavid Howells help 594786d35d4SDavid Howells Modules only use ELF REL relocations. Modules with ELF RELA 595786d35d4SDavid Howells relocations will give an error. 596786d35d4SDavid Howells 597cc1f0274SFrederic Weisbeckerconfig HAVE_IRQ_EXIT_ON_IRQ_STACK 598cc1f0274SFrederic Weisbecker bool 599cc1f0274SFrederic Weisbecker help 600cc1f0274SFrederic Weisbecker Architecture doesn't only execute the irq handler on the irq stack 601cc1f0274SFrederic Weisbecker but also irq_exit(). This way we can process softirqs on this irq 602cc1f0274SFrederic Weisbecker stack instead of switching to a new one when we call __do_softirq() 603cc1f0274SFrederic Weisbecker in the end of an hardirq. 604cc1f0274SFrederic Weisbecker This spares a stack switch and improves cache usage on softirq 605cc1f0274SFrederic Weisbecker processing. 606cc1f0274SFrederic Weisbecker 607235a8f02SKirill A. Shutemovconfig PGTABLE_LEVELS 608235a8f02SKirill A. Shutemov int 609235a8f02SKirill A. Shutemov default 2 610235a8f02SKirill A. Shutemov 6112b68f6caSKees Cookconfig ARCH_HAS_ELF_RANDOMIZE 6122b68f6caSKees Cook bool 6132b68f6caSKees Cook help 6142b68f6caSKees Cook An architecture supports choosing randomized locations for 6152b68f6caSKees Cook stack, mmap, brk, and ET_DYN. Defined functions: 6162b68f6caSKees Cook - arch_mmap_rnd() 617204db6edSKees Cook - arch_randomize_brk() 6182b68f6caSKees Cook 619d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_BITS 620d07e2259SDaniel Cashman bool 621d07e2259SDaniel Cashman help 622d07e2259SDaniel Cashman An arch should select this symbol if it supports setting a variable 623d07e2259SDaniel Cashman number of bits for use in establishing the base address for mmap 624d07e2259SDaniel Cashman allocations, has MMU enabled and provides values for both: 625d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MIN 626d07e2259SDaniel Cashman - ARCH_MMAP_RND_BITS_MAX 627d07e2259SDaniel Cashman 6285f56a5dfSJiri Slabyconfig HAVE_EXIT_THREAD 6295f56a5dfSJiri Slaby bool 6305f56a5dfSJiri Slaby help 6315f56a5dfSJiri Slaby An architecture implements exit_thread. 6325f56a5dfSJiri Slaby 633d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN 634d07e2259SDaniel Cashman int 635d07e2259SDaniel Cashman 636d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX 637d07e2259SDaniel Cashman int 638d07e2259SDaniel Cashman 639d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS_DEFAULT 640d07e2259SDaniel Cashman int 641d07e2259SDaniel Cashman 642d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_BITS 643d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address" if EXPERT 644d07e2259SDaniel Cashman range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX 645d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT 646d07e2259SDaniel Cashman default ARCH_MMAP_RND_BITS_MIN 647d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_BITS 648d07e2259SDaniel Cashman help 649d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 650d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 651d07e2259SDaniel Cashman resulting from mmap allocations. This value will be bounded 652d07e2259SDaniel Cashman by the architecture's minimum and maximum supported values. 653d07e2259SDaniel Cashman 654d07e2259SDaniel Cashman This value can be changed after boot using the 655d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_bits tunable 656d07e2259SDaniel Cashman 657d07e2259SDaniel Cashmanconfig HAVE_ARCH_MMAP_RND_COMPAT_BITS 658d07e2259SDaniel Cashman bool 659d07e2259SDaniel Cashman help 660d07e2259SDaniel Cashman An arch should select this symbol if it supports running applications 661d07e2259SDaniel Cashman in compatibility mode, supports setting a variable number of bits for 662d07e2259SDaniel Cashman use in establishing the base address for mmap allocations, has MMU 663d07e2259SDaniel Cashman enabled and provides values for both: 664d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MIN 665d07e2259SDaniel Cashman - ARCH_MMAP_RND_COMPAT_BITS_MAX 666d07e2259SDaniel Cashman 667d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN 668d07e2259SDaniel Cashman int 669d07e2259SDaniel Cashman 670d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX 671d07e2259SDaniel Cashman int 672d07e2259SDaniel Cashman 673d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 674d07e2259SDaniel Cashman int 675d07e2259SDaniel Cashman 676d07e2259SDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS 677d07e2259SDaniel Cashman int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT 678d07e2259SDaniel Cashman range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX 679d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT 680d07e2259SDaniel Cashman default ARCH_MMAP_RND_COMPAT_BITS_MIN 681d07e2259SDaniel Cashman depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS 682d07e2259SDaniel Cashman help 683d07e2259SDaniel Cashman This value can be used to select the number of bits to use to 684d07e2259SDaniel Cashman determine the random offset to the base address of vma regions 685d07e2259SDaniel Cashman resulting from mmap allocations for compatible applications This 686d07e2259SDaniel Cashman value will be bounded by the architecture's minimum and maximum 687d07e2259SDaniel Cashman supported values. 688d07e2259SDaniel Cashman 689d07e2259SDaniel Cashman This value can be changed after boot using the 690d07e2259SDaniel Cashman /proc/sys/vm/mmap_rnd_compat_bits tunable 691d07e2259SDaniel Cashman 6921b028f78SDmitry Safonovconfig HAVE_ARCH_COMPAT_MMAP_BASES 6931b028f78SDmitry Safonov bool 6941b028f78SDmitry Safonov help 6951b028f78SDmitry Safonov This allows 64bit applications to invoke 32-bit mmap() syscall 6961b028f78SDmitry Safonov and vice-versa 32-bit applications to call 64-bit mmap(). 6971b028f78SDmitry Safonov Required for applications doing different bitness syscalls. 6981b028f78SDmitry Safonov 6993033f14aSJosh Triplettconfig HAVE_COPY_THREAD_TLS 7003033f14aSJosh Triplett bool 7013033f14aSJosh Triplett help 7023033f14aSJosh Triplett Architecture provides copy_thread_tls to accept tls argument via 7033033f14aSJosh Triplett normal C parameter passing, rather than extracting the syscall 7043033f14aSJosh Triplett argument from pt_regs. 7053033f14aSJosh Triplett 706b9ab5ebbSJosh Poimboeufconfig HAVE_STACK_VALIDATION 707b9ab5ebbSJosh Poimboeuf bool 708b9ab5ebbSJosh Poimboeuf help 709b9ab5ebbSJosh Poimboeuf Architecture supports the 'objtool check' host tool command, which 710b9ab5ebbSJosh Poimboeuf performs compile-time stack metadata validation. 711b9ab5ebbSJosh Poimboeuf 712af085d90SJosh Poimboeufconfig HAVE_RELIABLE_STACKTRACE 713af085d90SJosh Poimboeuf bool 714af085d90SJosh Poimboeuf help 715af085d90SJosh Poimboeuf Architecture has a save_stack_trace_tsk_reliable() function which 716af085d90SJosh Poimboeuf only returns a stack trace if it can guarantee the trace is reliable. 717af085d90SJosh Poimboeuf 718468a9428SGeorge Spelvinconfig HAVE_ARCH_HASH 719468a9428SGeorge Spelvin bool 720468a9428SGeorge Spelvin default n 721468a9428SGeorge Spelvin help 722468a9428SGeorge Spelvin If this is set, the architecture provides an <asm/hash.h> 723468a9428SGeorge Spelvin file which provides platform-specific implementations of some 724468a9428SGeorge Spelvin functions in <linux/hash.h> or fs/namei.c. 725468a9428SGeorge Spelvin 726666047feSFinn Thainconfig HAVE_ARCH_NVRAM_OPS 727666047feSFinn Thain bool 728666047feSFinn Thain 7293a495511SWilliam Breathitt Grayconfig ISA_BUS_API 7303a495511SWilliam Breathitt Gray def_bool ISA 7313a495511SWilliam Breathitt Gray 732d2125043SAl Viro# 733d2125043SAl Viro# ABI hall of shame 734d2125043SAl Viro# 735d2125043SAl Viroconfig CLONE_BACKWARDS 736d2125043SAl Viro bool 737d2125043SAl Viro help 738d2125043SAl Viro Architecture has tls passed as the 4th argument of clone(2), 739d2125043SAl Viro not the 5th one. 740d2125043SAl Viro 741d2125043SAl Viroconfig CLONE_BACKWARDS2 742d2125043SAl Viro bool 743d2125043SAl Viro help 744d2125043SAl Viro Architecture has the first two arguments of clone(2) swapped. 745d2125043SAl Viro 746dfa9771aSMichal Simekconfig CLONE_BACKWARDS3 747dfa9771aSMichal Simek bool 748dfa9771aSMichal Simek help 749dfa9771aSMichal Simek Architecture has tls passed as the 3rd argument of clone(2), 750dfa9771aSMichal Simek not the 5th one. 751dfa9771aSMichal Simek 752eaca6eaeSAl Viroconfig ODD_RT_SIGACTION 753eaca6eaeSAl Viro bool 754eaca6eaeSAl Viro help 755eaca6eaeSAl Viro Architecture has unusual rt_sigaction(2) arguments 756eaca6eaeSAl Viro 7570a0e8cdfSAl Viroconfig OLD_SIGSUSPEND 7580a0e8cdfSAl Viro bool 7590a0e8cdfSAl Viro help 7600a0e8cdfSAl Viro Architecture has old sigsuspend(2) syscall, of one-argument variety 7610a0e8cdfSAl Viro 7620a0e8cdfSAl Viroconfig OLD_SIGSUSPEND3 7630a0e8cdfSAl Viro bool 7640a0e8cdfSAl Viro help 7650a0e8cdfSAl Viro Even weirder antique ABI - three-argument sigsuspend(2) 7660a0e8cdfSAl Viro 767495dfbf7SAl Viroconfig OLD_SIGACTION 768495dfbf7SAl Viro bool 769495dfbf7SAl Viro help 770495dfbf7SAl Viro Architecture has old sigaction(2) syscall. Nope, not the same 771495dfbf7SAl Viro as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2), 772495dfbf7SAl Viro but fairly different variant of sigaction(2), thanks to OSF/1 773495dfbf7SAl Viro compatibility... 774495dfbf7SAl Viro 775495dfbf7SAl Viroconfig COMPAT_OLD_SIGACTION 776495dfbf7SAl Viro bool 777495dfbf7SAl Viro 778d4703ddaSDeepa Dinamaniconfig 64BIT_TIME 779f3d96467SArnd Bergmann def_bool y 780d4703ddaSDeepa Dinamani help 781d4703ddaSDeepa Dinamani This should be selected by all architectures that need to support 782d4703ddaSDeepa Dinamani new system calls with a 64-bit time_t. This is relevant on all 32-bit 783d4703ddaSDeepa Dinamani architectures, and 64-bit architectures as part of compat syscall 784d4703ddaSDeepa Dinamani handling. 785d4703ddaSDeepa Dinamani 78617435e5fSDeepa Dinamaniconfig COMPAT_32BIT_TIME 78700bf25d6SArnd Bergmann def_bool !64BIT || COMPAT 78817435e5fSDeepa Dinamani help 78917435e5fSDeepa Dinamani This enables 32 bit time_t support in addition to 64 bit time_t support. 79017435e5fSDeepa Dinamani This is relevant on all 32-bit architectures, and 64-bit architectures 79117435e5fSDeepa Dinamani as part of compat syscall handling. 79217435e5fSDeepa Dinamani 7930d4a619bSChristoph Hellwigconfig ARCH_NO_COHERENT_DMA_MMAP 7940d4a619bSChristoph Hellwig bool 7950d4a619bSChristoph Hellwig 79687a4c375SChristoph Hellwigconfig ARCH_NO_PREEMPT 79787a4c375SChristoph Hellwig bool 79887a4c375SChristoph Hellwig 799a50a3f4bSThomas Gleixnerconfig ARCH_SUPPORTS_RT 800a50a3f4bSThomas Gleixner bool 801a50a3f4bSThomas Gleixner 802fff7fb0bSZhaoxiu Zengconfig CPU_NO_EFFICIENT_FFS 803fff7fb0bSZhaoxiu Zeng def_bool n 804fff7fb0bSZhaoxiu Zeng 805ba14a194SAndy Lutomirskiconfig HAVE_ARCH_VMAP_STACK 806ba14a194SAndy Lutomirski def_bool n 807ba14a194SAndy Lutomirski help 808ba14a194SAndy Lutomirski An arch should select this symbol if it can support kernel stacks 809ba14a194SAndy Lutomirski in vmalloc space. This means: 810ba14a194SAndy Lutomirski 811ba14a194SAndy Lutomirski - vmalloc space must be large enough to hold many kernel stacks. 812ba14a194SAndy Lutomirski This may rule out many 32-bit architectures. 813ba14a194SAndy Lutomirski 814ba14a194SAndy Lutomirski - Stacks in vmalloc space need to work reliably. For example, if 815ba14a194SAndy Lutomirski vmap page tables are created on demand, either this mechanism 816ba14a194SAndy Lutomirski needs to work while the stack points to a virtual address with 817ba14a194SAndy Lutomirski unpopulated page tables or arch code (switch_to() and switch_mm(), 818ba14a194SAndy Lutomirski most likely) needs to ensure that the stack's page table entries 819ba14a194SAndy Lutomirski are populated before running on a possibly unpopulated stack. 820ba14a194SAndy Lutomirski 821ba14a194SAndy Lutomirski - If the stack overflows into a guard page, something reasonable 822ba14a194SAndy Lutomirski should happen. The definition of "reasonable" is flexible, but 823ba14a194SAndy Lutomirski instantly rebooting without logging anything would be unfriendly. 824ba14a194SAndy Lutomirski 825ba14a194SAndy Lutomirskiconfig VMAP_STACK 826ba14a194SAndy Lutomirski default y 827ba14a194SAndy Lutomirski bool "Use a virtually-mapped stack" 828ba14a194SAndy Lutomirski depends on HAVE_ARCH_VMAP_STACK && !KASAN 829ba14a194SAndy Lutomirski ---help--- 830ba14a194SAndy Lutomirski Enable this if you want the use virtually-mapped kernel stacks 831ba14a194SAndy Lutomirski with guard pages. This causes kernel stack overflows to be 832ba14a194SAndy Lutomirski caught immediately rather than causing difficult-to-diagnose 833ba14a194SAndy Lutomirski corruption. 834ba14a194SAndy Lutomirski 835ba14a194SAndy Lutomirski This is presently incompatible with KASAN because KASAN expects 836ba14a194SAndy Lutomirski the stack to map directly to the KASAN shadow map using a formula 837ba14a194SAndy Lutomirski that is incorrect if the stack is in vmalloc space. 838ba14a194SAndy Lutomirski 839ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX 840ad21fc4fSLaura Abbott def_bool n 841ad21fc4fSLaura Abbott 842ad21fc4fSLaura Abbottconfig ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 843ad21fc4fSLaura Abbott def_bool n 844ad21fc4fSLaura Abbott 845ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_KERNEL_RWX 846ad21fc4fSLaura Abbott def_bool n 847ad21fc4fSLaura Abbott 8480f5bf6d0SLaura Abbottconfig STRICT_KERNEL_RWX 849ad21fc4fSLaura Abbott bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX 850ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_KERNEL_RWX 851ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 852ad21fc4fSLaura Abbott help 853ad21fc4fSLaura Abbott If this is set, kernel text and rodata memory will be made read-only, 854ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 855ad21fc4fSLaura Abbott protection against certain security exploits (e.g. executing the heap 856ad21fc4fSLaura Abbott or modifying text) 857ad21fc4fSLaura Abbott 858ad21fc4fSLaura Abbott These features are considered standard security practice these days. 859ad21fc4fSLaura Abbott You should say Y here in almost all cases. 860ad21fc4fSLaura Abbott 861ad21fc4fSLaura Abbottconfig ARCH_HAS_STRICT_MODULE_RWX 862ad21fc4fSLaura Abbott def_bool n 863ad21fc4fSLaura Abbott 8640f5bf6d0SLaura Abbottconfig STRICT_MODULE_RWX 865ad21fc4fSLaura Abbott bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX 866ad21fc4fSLaura Abbott depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES 867ad21fc4fSLaura Abbott default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT 868ad21fc4fSLaura Abbott help 869ad21fc4fSLaura Abbott If this is set, module text and rodata memory will be made read-only, 870ad21fc4fSLaura Abbott and non-text memory will be made non-executable. This provides 871ad21fc4fSLaura Abbott protection against certain security exploits (e.g. writing to text) 872ad21fc4fSLaura Abbott 873ea8c64acSChristoph Hellwig# select if the architecture provides an asm/dma-direct.h header 874ea8c64acSChristoph Hellwigconfig ARCH_HAS_PHYS_TO_DMA 875ea8c64acSChristoph Hellwig bool 876ea8c64acSChristoph Hellwig 8777a46ec0eSKees Cookconfig ARCH_HAS_REFCOUNT 8787a46ec0eSKees Cook bool 8797a46ec0eSKees Cook help 8807a46ec0eSKees Cook An architecture selects this when it has implemented refcount_t 8817a46ec0eSKees Cook using open coded assembly primitives that provide an optimized 8827a46ec0eSKees Cook refcount_t implementation, possibly at the expense of some full 8837a46ec0eSKees Cook refcount state checks of CONFIG_REFCOUNT_FULL=y. 8847a46ec0eSKees Cook 8857a46ec0eSKees Cook The refcount overflow check behavior, however, must be retained. 8867a46ec0eSKees Cook Catching overflows is the primary security concern for protecting 8877a46ec0eSKees Cook against bugs in reference counts. 8887a46ec0eSKees Cook 889fd25d19fSKees Cookconfig REFCOUNT_FULL 890fd25d19fSKees Cook bool "Perform full reference count validation at the expense of speed" 891fd25d19fSKees Cook help 892fd25d19fSKees Cook Enabling this switches the refcounting infrastructure from a fast 893fd25d19fSKees Cook unchecked atomic_t implementation to a fully state checked 894fd25d19fSKees Cook implementation, which can be (slightly) slower but provides protections 895fd25d19fSKees Cook against various use-after-free conditions that can be used in 896fd25d19fSKees Cook security flaw exploits. 897fd25d19fSKees Cook 89804f264d3SPaul Burtonconfig HAVE_ARCH_COMPILER_H 89904f264d3SPaul Burton bool 90004f264d3SPaul Burton help 90104f264d3SPaul Burton An architecture can select this if it provides an 90204f264d3SPaul Burton asm/compiler.h header that should be included after 90304f264d3SPaul Burton linux/compiler-*.h in order to override macro definitions that those 90404f264d3SPaul Burton headers generally provide. 90504f264d3SPaul Burton 906271ca788SArd Biesheuvelconfig HAVE_ARCH_PREL32_RELOCATIONS 907271ca788SArd Biesheuvel bool 908271ca788SArd Biesheuvel help 909271ca788SArd Biesheuvel May be selected by an architecture if it supports place-relative 910271ca788SArd Biesheuvel 32-bit relocations, both in the toolchain and in the module loader, 911271ca788SArd Biesheuvel in which case relative references can be used in special sections 912271ca788SArd Biesheuvel for PCI fixup, initcalls etc which are only half the size on 64 bit 913271ca788SArd Biesheuvel architectures, and don't require runtime relocation on relocatable 914271ca788SArd Biesheuvel kernels. 915271ca788SArd Biesheuvel 916ce9084baSArd Biesheuvelconfig ARCH_USE_MEMREMAP_PROT 917ce9084baSArd Biesheuvel bool 918ce9084baSArd Biesheuvel 919fb346fd9SWaiman Longconfig LOCK_EVENT_COUNTS 920fb346fd9SWaiman Long bool "Locking event counts collection" 921fb346fd9SWaiman Long depends on DEBUG_FS 922fb346fd9SWaiman Long ---help--- 923fb346fd9SWaiman Long Enable light-weight counting of various locking related events 924fb346fd9SWaiman Long in the system with minimal performance impact. This reduces 925fb346fd9SWaiman Long the chance of application behavior change because of timing 926fb346fd9SWaiman Long differences. The counts are reported via debugfs. 927fb346fd9SWaiman Long 9282521f2c2SPeter Oberparleitersource "kernel/gcov/Kconfig" 92945332b1bSMasahiro Yamada 93045332b1bSMasahiro Yamadasource "scripts/gcc-plugins/Kconfig" 931fa1b5d09SLinus Torvalds 93222471e13SRandy Dunlapendmenu 933